Senate Republicans had hoped that Donald Trump’s Cabinet selections could give them a leg up in the 2018 midterm races.

So far, things aren’t going to plan.

The president-elect on Tuesday offered Montana GOP Rep. Ryan Zinke the post of Interior secretary, according to a source familiar with the offer. The former Navy SEAL and trained geologist first won election to the state’s at-large House seat just two years ago.

The problem? Zinke was a likely opponent of Democratic Sen. Jon Tester, who faces re-election in 2018 and is considered one of the GOP’s top targets. In interviews, Zinke was already openly discussing a run against the incumbent Democrat.

Taking the job at the Department of the Interior wouldn’t necessarily prevent the GOP lawmaker from running against Tester, and the state’s relatively late primary — to be held on June 5, 2018 — gives him a little more time to leave the Trump administration and prepare for a run.

But it certainly would make a campaign much less likely and leave Republicans without a candidate that some of the party’s strategists had already penciled in as the GOP nominee.

One Republican operative, granted anonymity to speak candidly, said Trump’s decision leaves the GOP with few other options.

“Just not enough statewide elected Republicans to have a real bench,” the operative said. “Fingers crossed for [Montana GOP Attorney General] Tim Fox.”

Senate Republicans weren’t supposed to be the ones who were hurt by Trump’s Cabinet selections. The GOP had hoped that the president-elect would nominate some Senate Democrats to join his administration, removing them from vulnerable seats and clearing the way for Republicans to expand their 52-seat majority.

That hasn’t happened yet: On Tuesday, Democratic Sen. Joe Manchin III of West Virginia said he would remain a senator after Trump picked former Texas Gov. Rick Perry over Manchin to be his Energy secretary.

Manchin is one of the few Democrats left who could plausibly win statewide in West Virginia, which went heavily for Trump last month. Many Republicans were eager for him to leave, confident that a replacement would have a harder time holding the seat. (Some Republicans do believe that Manchin’s tenure in Washington since first winning election in 2010 makes him an easier target in 2018.)

Trump can still pick one Senate Democrat from a vulnerable state: Heidi Heitkamp of North Dakota, who is reportedly a favorite to become secretary of Agriculture. If the popular incumbent left the Senate, Democrats would have a hard time finding a candidate who could win in the deep-red state.

But if Trump passes on Heitkamp, Democrats will still have a fighting chance to retain her seat. And Senate Republicans will wonder what went wrong.